This invention relates to a camera mountable with a film cartridge, in particular to a camera mountable with an APS or advanced photosystem film cartridge.
A technique for effecting a film feed such as winding and rewinding by a torque of an electric motor built in a camera main body is known, and the film is fed by driving a motor in most of cameras presently available on the market.
The film is wound by rotating a take-up spool provided in a film take-up chamber, whereas it is rewound by rotating a fork provided in a cartridge chamber and fitted into a spool of a cartridge. Different members are driven to wind and rewind the film, and contents of controls for winding and rewinding of the film differ (the film is wound frame by frame, whereas the entire length of the pulled out film is rewound into the cartridge). Accordingly, a conventional drive mechanism for winding and rewinding the film by driving of the motor is such that a torque acting in one rotating direction of the single electric motor is transmitted to the fork in the cartridge chamber and a torque acting in the opposite rotating direction thereof is transmitted to the take-up spool in the film take-up chamber by means of a planetary transmission switching mechanism.
In recent years, film cartridges in accordance with the APS (hereinafter, APS film cartridge) have been standardized and commercialization of cameras which use such films have been promoted.
The APS film cartridge is provided with a light blocking lid at a film outlet of a cartridge and a film is completely contained in the cartridge as disclosed in, e.g. U.S. Pat. No. 5,347,334. Accordingly, the cartridge functions not only as a container for an unexposed film, but also as a container for a developed film.
Further, a bar code plate which enables the detection of the type of a contained film (unexposed film, exposed film, incompletely exposed film, etc.) is integrally rotatably provided at one end of the spool. Type of the film is detectable by reading a bar code on the bar code plate. Accordingly, a proper photo-processing can be applied in accordance with the type of the contained film independently of which type of a film cartridge is loaded in the camera.
Furthermore, the APS film cartridge is smaller than the conventional 35 mm film cartridge (the radial and longitudinal dimensions of the container or cartridge are reduced by about 4 mm, and an image recording area of the film is reduced by about 40%), contributing to downsizing the camera main body.
Since the film is completely contained in the cartridge in the APS film cartridge as described above, the APS film cartridge needs to be loaded by automatically pulling the film out of the cartridge after opening the light blocking lid when it is loaded in the camera. On the other hand, when the APS film cartridge is taken out of the camera, the light blocking lid needs to be closed after the pulled out film is completely rewound into the cartridge. For example, as compared with a 135 type roll film, a more complicated film feeding control is necessary for the APS film cartridge. Therefore, in the camera which uses the APS film cartridge, the motor-driving is essential for the film feed control and driving is necessary not only to wind and rewind the film, but also to load the film and open/close the light blocking lid which are not necessary with the conventional films.
Also, in the case where there is provided a lockable cover for closing the cartridge chamber for accommodating the film cartridge, it is desirable to automatically release a cover lock and open the cartridge cover.
In the camera using the conventional 135 type roll film, since the rewinding fork and the take-up spool are not controllably driven in connection with each other, winding/rewinding can be done by switching the rotating direction of the single electric motor. Accordingly, it is possible to facilitate the drive control. In the camera using the APS film cartridge, the rewinding fork and the take-up spool needs to be simultaneously controllably driven for loading of the film after defining a specified relationship between them and a new drive mechanism is necessary to open and close the light blocking lid. However, if special motors are separately provided to drive the respective members such as the rewinding fork, the take-up spool, and the light blocking lid, there are required more elements for the construction of the camera and a complicated drive control for the respective motors. This is against a downsizing tendency of the APS film cartridge and is not necessarily effective.